Power transmission.



J. G. P. THOMAS POWER TRANSMISSION APPLICATION FILED OCT-11,1913.

Patented Apr. 2, 1918.

2 SHEETS-SHEET 1.

J. G. P. THOMAS.

POWER TRANSMISSION.

APPLICATION FILED OCT. 11. 1913.

1,261,069. Patented Apr. 2, 1918.

2 SHEETS-SHEET 2- UNITED STATES PA QFFICE.

JOHN GODFREY PARRY THOMAS, OF CHISWICK, LONDON, ENGLAND, ASSIGNOB 'I'OTHOMAS FOREIGN PATENTS LIMITED, OF KENSINGTON, LONDON, ENGLAND, A

. CORPORATION OF GREAT BRITAIN.

POWER TRANSMISSION.

- Specification of Letters Patent.

Patented Apr. 2, 1918.

To all whom it may concern:

Be it known that I, JoHN Gonrnnv PARRY THOMAS, a subject of the King ofGreat Britain, residing at 21 Ennismore avenue, Chiswi'ck, in the countyof London,

England, have invented new and useful Improvements in PowerTransmissions, of which the following is. a specification.

The present invention relates to the application of electromechanicalpower trans mission systems to motor vehicles.

Various systems are already known of driving load shafts in which aprime motor commonly a petrol or similar internal combustion engineinstead of driving the load directly through mechanical gearing iscombined with dynamo electric machines through the medium of which itspower is transmitted to the load shaft and the speed of the latter isregulated as desired. In particular there are electromechanical powertransmission systems in which two dynamo electric machines, one of themmechanically connected to the load shaft, are inter-connected with eachother, and the prime motor through an epicyclic or balance gearing. Byway of example, a system of this kind invented by the present applicantis referred to hereinafter.

The invention forming the subject of the present application for LettersPatent is concerned not with any modification of such systems consideredpurely as transmission systems, but rather with their application to the(lIiViIlg of motor vehicles. It consists in the first place in animproved disposition upon the vehicle of the various machines orelements, constituting such systems; and in corresponding improvementsin the arrangement of the necessary gearing. It consists further in theprovision of means which enable the dynamo electric machines of thetransmission system to function either as elements of that system or asindependent electric motors, receiving their supply from a separatesource; such means including independent control apparatus forcontrolling the said machines in their new function. V

The invention is illustrated by the accompanying drawings, in whichFigure 1 shows a diagram of connections of one of the known systems withwhich the invention deals, taken merely as an example.

Fig. 2 shows in side elevation the main featuresof the mechanicaldisposition of the elements.

Fig. 3 is a plan of Fig. 2 showing the various gearings in section.

Fig. 4 is a diagram of the electrical connections employed,

It should be clearly understood that Fig. 1 exhibits no novelty formingpart of the present invention. It. is a diagram of electricalconnections illustrating the operation of an electromechanical[transmission system invented by the present applicant and fullydescribed and illustrated in the specification and drawings of hisUnited States Patent No. 948436, which system has been selected as anexample of the systems with which the present invention is concerned.

In this system two dynamo electric machines 6, 7 and 20, 21 areconnected together and to the prime driving motor by means of anepicyclic or balance gearing. The machine 20, 21 has its armaturemechanically connected to the load shaft. One clutch serves for feedingthe prime motor in the usual Way, and another clutch, the members ofwhich are connected with the armature shafts of the machines 6, 7, and20, 21, enables the epicyclic gearing to be locked so that it rotates asa whole, forcing the prime motor and the two dynamo electric machines torotate at the same speed. The machines 6, 7 and 20, 21 are electricallyconnected as shown in Fig. i. The fields 7, 21, are, in one exampleillustrated in the prior patent, excited by current derived from thearmatures 6, 20, as also shown in Fig. 1, the machines being serieswound. Means are profield 21. Hence by means of these switches \1arranged in practice in a controller the machines are enabled to gothrough the functions set out in detail in the specification of theprevious patent.

When such a system as this has to be applied to a vehicle in such cases,forexample, where the vehicle has a short wheel base, it is inconvenientto arrange the prime motor and the dynamo electric machines with theirshafts in line as suggested in the prior specification above referredto. It is not desirable to mount the dynamo electric machines directlyon the axles of the vehicle as has been proposed hitherto, because thatinvolves too much dead weight upon the axles, and moreover dynamoelectric machines cannot be designed conveniently to rotate at thecomparatively low speeds of the axles of the vehicle.

In accordance with the present invention the desired economy of spaceand convenienceof arrangement is secured by the adoption of a type ofsuspension similar to that used for the motors of road cars or tram carsor for motors employed in electric railway practice. Dynamo electricmachines are set with their shafts parallel to the axles of the vehiclewheels, while the prime motor shaft may be either parallel or at rightangles, whichever may be the more convenient in particular cases; andthe casings of the electrical machines rest in part upon the vehicleaxles and in part are borne upon springs, for example, by blocks, movingin arc-shaped guides. The epicyclic or differential gearing throughwhich the machines have to be connected is arranged co-axially with oneof the machines in its casing, and as the other machine is preferablylocated on the other axle and geared thereto by ordinary road cargearing the mechanical connection between the two machines is throughthe wheels and running surface. When both dynamo electric machines arethus geared to the axles of the vehicle they can, in case of need, beused to drive those axles directly, taking their supply from an overheador other external conductor or a battery, instead of being driven fromthe prime motor carried upon thevehicle.

These novel features appear more particularly in Figs. 2 and 3 of theaccompanying drawings, which will now be described in detail. A suitableprime motor such as an internal combustion'engine 12 is mounted upon thevehicle. The engine 12 is connected through a clutch 13 and gearinghereinafter described with one axle 10 of the vehicle. Through thewheels 18 and track 19 therefore the prime motor is also in effectconnected with the second axle 10 of the vehicle, to which is geared asecond dynamo electric machine 20, 21.

The balance gearing by which the two electrical machines 6, 7, and 20,21 and the prime motor 12 are connected together, comprises a casing 1formingthe carrier for the spindles of planet wheels 2, 3, which meshrespectively with sun wheels 4, 5. Of these the latter is on the shaftof the dynamo electric machine 6, 7. The second dynamo electric machine20, 21, having exactly the same function as that in the above mentioneda. a specification, and shown in Fig. 1 1s shown in Fig. 3 mounted uponthesecond axle 10 of the vehicle. It is thus mechanically coupled withmachine 6, 7, through the gearing 31, 32 of the roadcar or tram cartype, the wheels of the vehicle, the track on which they run and thegearing 8, 9 by which the axle 10 is connected with the sun wheel 4.

A clutch 11 indicated as a dog clutch but which instead may be anysuitable friction clutch serves to put the epicyclic gearing out ofactionin the arrangement shown this is effected by making fast thecasing 1 or planet carrier to the larger sun wheel 4.

In the construction illustrated the prime motor 12 is shown as havingits shaft at right angles to the axles 10, 10 of the vehi cle, and itdrives the planet carrier 1 of the epicyclic gearing through a clutch 13and bevel pinion 14, which latter meshes with bevel teeth 15 formed onthe circumference of the casing or planet carrier. The gearing 14', 15may be replaced by worm gearing. If desired, however, the prime motor 12could be set with its shaft parallel to the vehicle rails, and coulddrive the planet carrier 1 through spur gearing or belts or chains.

The dynamo electric machine 6, 7, together with the balance gearing andthe clutch 11 may conveniently be mounted together in a frame 16, whichis in part slung from the axle 10 and in part carried by blocks 17supported by springs 28 in arc-shaped guides 29 in a manner well knownin electric rail and tramway practice. The frame 30 containing thesecond dynamo electric machine 20, 21 is similarly mounted with respectto the second axle 10, as seen to the right hand of Fig. 2.

It will be understood that when the vehicle is being driven by its ownprime motor 12 the clutch 13 is put in and rendered operative and theclutch 11 is out of action except on top speed. The speed control iseflected by electric control of the dynamo electric machines 6, 7, and20, 21, as fully described in the specification of" the prior patentmentioned above. For the purpose of this control the dynamo electricmachines 6, 7, and 20, 21, are joined by conductors 22 to a suitablecontroller 23. In addition, however, to the rheostats and controlapparatus necessary for this mode of running further provision may bemade for running and controlling the dynamo electric machines like thetwo motors of a tram car by any of the systems commonly employed forsuch purposes.

When it is desired to drive the vehicle by aid of an overhead conductorthe clutch 13 is put out of action and the engine 12 is stopped, whilethe clutch 11 is at in. The alternative system of control is rought intooperation and the vehicle is then driven purely electrically. Thisalternative system of control comprises suitable controlling means 24(Fig. 4), which -is joined to the machines 6, 7, and 20, 21, and alsothrough the trolley 25 to the overhead conductor 26 or other source ofpower, as well as being grounded by connection to the vehicle frame 27and thus to the rails which commonly serve as the return conductor.

With the clutch 11 in the position illustrated in Fig. 3 it will benoted that when the clutch is engaged and the machine 6, 7, acting as amotor the axle 10 is driven through the balance gearing which isundesirable, especially if there is any back lash in the gearing. Thisdifficulty, however, is

readily avoided by introducing the clutch 11 between the planet carrier1 and the shaft of the armature itself, in which position it servesequally well the function of locking the gear solid.

When it is unnecessary to drive two axles of the vehicle for the sake ofutilizing the adhesion of four wheels both dynamo electric machines maybe suspended from the same axle. The arrangement may be applied to bogievehicles as well as to. those with single axles.

What I claim is:

1. A motor vehicle comprising a frame, a prime motor carried thereby,two dynamo electric machines, wheels and axles, balance gearinginterconnecting one of said dynamo electric machines with said primemotor and one axle, gearing connecting the other dynamo electric machinewith another axle, a clutch for disengaging said prime motor from saidmachines, a separate electrical source of supply, means for controllingsaid dynamo electric machines as parts of an electromechanicaltransmission system and means for controlling said machines as motorsconnectedwith the separate source of suppl 2. X motor vehicle comprisinga frame, wheels and axles, a prime motor upon said frame, dynamoelectric machines, means for driving said wheels from said prime motorby the aid of said dynamo electric machines,

balance gearing of the three-member type supported from said machine,and having one member connected thereto, means partially suspending saiddynamo electric machine and a balance gear on said axle, a prime motorconnected with another member of said balance gear, means connecting thethird member of said'balance gear with said axle, means fordisconnecting said prime motor and means for directly gearing saiddynamo electric machine to said axle.

4:. In a motor vehicle the combination with one axle of a casing partlysuspended therefrom, a dynamo electric machine in said casing, a balancegearing of the three-member type in said casing having one memberconnected to said dynamo electric machine, means for driving .a secondmember, gearing connecting the third member with the axle, and means forlocking the balance gearing.

5. A motor vehicle comprising a frame, axles and wheels, a prime motorupon said frame, dynamo electric machines hung from different axles,means for mechanically interconnecting said prime motor and said dynamoelectric machines, and means for directly gearing said dynamo electricmachines to said axles.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

JOHN GODFREY PARRY THOMAS.

